The present invention relates to smart card manufacturing processes, and specifically a hybrid contact-contactless manufacturing process of a smart card, the antenna of which is on a support made of fibrous material such as paper.
The contactless smart card is a system being used increasingly in various sectors. In the transport sector, the card has been developed as a means of payment. The same holds true for the electronic wallet. Many companies have also developed identification means for their personnel using contactless smart cards.
The exchange of information between a hybrid contact-contactless card and the associated reader takes place via remote electromagnetic coupling between an antenna embedded in the contactless card and a second antenna located in the reader or directly by contact with the reader. In order to create, store and process the information, the card is equipped with an electronic module which is connected to the antenna. The antenna is generally located on a dielectric support made of plastic material. The standard industrial manufacturing process can be broken down into three steps:
the antenna is made on a plastic dielectric support (polyvinyl chloride (PVC), polyesters (PET), polycarbonate (PC) . . . ) (polyvinyl chloride (PVC), polyesters (PET), polycarbonate (PC) . . . ) using copper or aluminum etching techniques,
hot-lamination under pressure of the upper and lower plastic layers of the card body (PVC, PET, PC, acrylonitrile-butadiene-styrene (ABS) . . . ), onto the antenna support in order to create a monobloc card.
placement and connection of an electric module using electrically conductive glue.
However, this process generates several major drawbacks. The process leads to a composite stack of glued or heat bonded plastic materials with different thermal expansion coefficients. As a result, systematic unacceptable and irreversible distortion of the cards is observed (twisting, warping), as well as a lack of mechanical resistance when subjected to standardized or equivalent tests.
Furthermore, PVC exhibits poor thermomechanical properties. During the lamination process, material flow is significant and the antenna""s shape factor is not maintained. This leads to antenna malfunction as the electrical parameters (inductance and resistance) vary. It is not uncommon to experience antenna breakage in areas subjected to strong sheer stresses. This is particularly the case in angles and at electrical bridging points.
The laminated ISO cards have a total thickness between 780 and 840 m. Considering the material flows described above, it is also very difficult to guarantee customers a narrow and controlled distribution of the cards"" population. operation creates a monobloc card with poor mechanical properties in terms of the restitution of absorbed stresses: during standardized bending and twisting tests, all of the stress applied is transmitted to the electronic module and primarily to the bonding points which make the connections. The mechanical strength of the bonding joints is subjected to great strain and the slightest imperfection in the bond causes the modulexe2x80x94antenna connection to break.
After lamination, the imprint from the copper etching is visible on the printed card bodies. Although this does not prevent the card from operating correctly, the defect is often emphasized by users who are very concerned about the aesthetic criteria.
Furthermore, the cost of manufacturing the card with this process is too high to enable any real increase in its usage.
Lastly, the processes currently used does not produce cards with the possibility to view the poor mechanical treatment inflicted on them by the users, particularly with the intent to commit fraud. It is in fact relatively easy for someone with experience in card fraud to destroy the card by folding it repeatedly without it being possible to easily prove any malicious intent afterwards. For example, the antenna may be cut without the card being marked. Commercial policies set up within companies generally ensure the replacement of defective cards free of charge. The systematic replacement of these cards is a source of major supplementary costs for these companies.
The purpose of the invention is to mitigate these drawbacks by supplying an inventive manufacturing process using a support made of fibrous material on which an antenna is screen printed using electrically conductive ink, thereby significantly reducing the production costs of hybrid or contactless smart cards.
The invention thus relates to a manufacturing process of a hybrid contact-contactless smart card with an antenna support made of fibrous material such as paper, including the following steps:
A manufacturing process of the antenna consisting in screen printing turns of electrically conductive polymer ink on a support made of fibrous material and to subject said support to a heat treatment process in order to bake the ink,
A step for laminating the card bodies onto the antenna support consisting in welding, on each side of the support, at least two sheets of plastic material, forming the card bodies, by a hot press molding technique,
A cavity milling step consisting in piercing, in one of the card bodies, a cavity for housing the module comprised by the chip and the double-sided circuit, the cavity including a smaller internal portion which receives the chip and a larger external portion for receiving the double-sided circuit, the cavity being dug into the card body which is opposite the side of the support featuring the electrically conductive screen printed ink forming the antenna, and the milling operation enabling the connection pads to be removed, and
a module insertion step consisting in using a glue enabling the module to be secured and a glue containing silver for connecting the module to the connectors, and to position it in the cavity provided for this purpose.